Polymeric foam and scrim sheathings

ABSTRACT

A sheathing adapted to be fastened to at least one wall supporting structure comprises at least two layers. The first layer comprises a polymeric foam layer. The second layer comprises a polymeric scrim and is located adjacent to the first layer. The second layer has a first portion and a second portion. The second portion is located near the periphery of the polymeric scrim layer. The first portion has a first machine direction (MD) scrim count number and a first transverse direction (TD) scrim count number, and the second portion has a second MD scrim count number and a second TD scrim count number. At least one of the second MD scrim count number and the second TD scrim count number is greater than the respective first MD scrim count number or the first TD scrim count number so as to inhibit failure of the scrim.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a Continuation-in-Part of U.S. patentapplication Ser. No. 09/421,031 filed on Oct. 20, 1999.

FIELD OF THE INVENTION

[0002] The present invention relates generally to sheathings that areused in structures and, more particularly, to polymeric foam sheathingmaterials that are used in prefabricated housing, site built housing,and remodeling.

BACKGROUND OF THE INVENTION

[0003] There are different commercial sheathings that are used in theconstruction of buildings. Sheathings include materials that span theframe supports of buildings. Some of the commercial products that havebeen used as sheathing include thin composite laminations, fiberboard,orientated strand board (OSB) and plywood. Some of these productsprovide structural strength, durability and/or rigidity. These products,however, have disadvantages such as being heavy and difficult toinstall, providing little insulation and/or having poor moistureresistance.

[0004] There are other commercial products that are available assheathing. For example, polyisocyanurate foam, extruded polystyrenefoam, and molded expanded polystyrene (EPS) foam. These existing foamedmaterials generally have advantages such as increased insulation andeasier handling. These existing foamed materials, however, havedisadvantages such as their lack of strength as measured by windresistance. This is shown, for example, by their failures to withstand100 miles per hour winds when installed. Lack of wind resistance maycause problems such as fracturing, cracking and/or edge pull out of thesheathing from the fasteners. During the pulling of the edge of thematerial, the fastener generally remains, but the sheathing is pulledaway.

[0005] Existing foam sheathing is still susceptible to damage at thebuilding site prior to installation. This problem is further evidentwhen, for example, delays occur in the installation and/or theinstallation occurs in extreme weather conditions. One common example ofdamage that may occur is when a piece breaks off from a remainder of thesheathing during the process of installation or by vandalism afterinstallation at the building site before being covered with an exteriorfacing such as siding, brick, or stucco.

[0006] Accordingly, a need exists for a sheathing material for use inprefabricated housing, site built housing, and remodeling that overcomesthe above-noted shortcomings associated with existing sheathing.

SUMMARY OF THE INVENTION

[0007] According to one embodiment of the present invention, a sheathingadapted to be fastened to at least one wall supporting structurecomprises at least two layers. The first layer comprises a polymericfoam layer. The second layer comprises a polymeric scrim and is locatedadjacent to the first layer. The second layer has a first scrim portionand a second portion. The second portion is located near the peripheryof the polymeric scrim layer. The first portion has a first machinedirection (MD) scrim count number and a first transverse direction (TD)scrim count number, and the second portion has a second MD scrim countnumber and a second TD scrim count number. At least one of the second MDscrim count number and the second TD scrim count number is greater thanthe respective first MD scrim count number or the first TD scrim countnumber so as to inhibit failure of the scrim.

[0008] According to another embodiment, a sheathing adapted to befastened to at least one wall supporting structure comprises at leasttwo layers. The first layer comprises a polymeric foam layer and islocated adjacent the second layer. The second layer comprises apolymeric scrim having a uniform scrim count number. The polymeric scrimhas a machine direction (MD) scrim count number which is least 18 and atransverse direction (TD) scrim count number which is at least 4 so asto inhibit failure of the scrim.

[0009] According to another embodiment of the present invention, asheathing adapted to be fastened to at least one wall supportingstructure comprises at least three layers. The first layer comprises apolymeric foam layer. The second layer comprises a polymeric scrim andhas a first portion and a second portion. The second portion is locatednear the periphery of the polymeric scrim layer. The first portion has afirst machine direction (MD) scrim count number and a first transversedirection (TD) scrim count number, and the second portion has a secondMD scrim count number and a second TD scrim count number. At least oneof the second MD scrim count number and the second TD scrim count numberis greater than the respective first MD scrim count number or the firstTD scrim count number so as to inhibit failure of the scrim. The thirdlayer comprises an impact polystyrene and is located between the firstand the second layers.

[0010] According to one method of the present invention, a sheathing isprovided that comprises at least two layers. The first layer comprises apolymeric foam layer. The second layer comprises a polymeric scrim andis located adjacent to the first layer. The second layer has a firstportion and a second portion. The second portion is located near theperiphery of the polymeric scrim layer. The first portion has a firstmachine direction (MD) scrim count number and a first transversedirection (TD) scrim count number, and the second portion has a secondMD scrim count number and a second TD scrim count number. At least oneof the second MD scrim count number and the second TD scrim count numberis greater than the respective first MD scrim count number or the firstTD scrim count number so as to inhibit failure of the scrim. Thesheathing is installed to a wall supporting structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 shows a side view of a two-layer sheathing according to oneembodiment of the present invention.

[0012]FIGS. 2a and 2 b show front views of the second layer of thesheathing according to two embodiments of the present invention.

[0013]FIG. 3 shows a side view of a three-layer sheathing according toanother embodiment of the present invention.

[0014]FIG. 4 shows a side view of a four-layer sheathing according toanother embodiment of the present invention.

[0015]FIG. 5 shows a side view of a five-layer sheathing according toyet another embodiment of the present invention.

[0016]FIG. 6 shows a side view of a seven-layer sheathing according to afurther embodiment of the present invention.

[0017]FIG. 7 shows a cut-away perspective view of a five-layer sheathingfastened to a wall supporting structure according to one embodiment ofthe present invention using the second layer embodiment depicted in FIG.2a.

[0018]FIG. 8 shows a schematic flow diagram of an overall sequence ofoperations according to one process involved in the manufacture of athree-layer sheathing such as that shown in FIG. 3.

[0019] While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular forms disclosed but, on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theappended claims.

DESCRIPTION OF SPECIFIC EMBODIMENTS

[0020] Turning now to the drawings and referring initially to FIG. 1, atwo-layer sheathing 10 is shown according to one embodiment of thepresent invention. The sheathings of the present invention, includingsheathing 10, are adapted to be fastened to a wall supporting structure.On a building, sheathings are typically covered by an exterior facingsuch as siding, brick or stucco. The sheathing 10 of FIG. 1 comprises apolymeric scrim layer 12 and a polymeric foam layer 14. The polymericscrim layer 12 of the present invention provides additional strength anddurability to the polymeric foam layer 14.

[0021] Polymeric Scrim Layer

[0022] The polymeric scrim layer 12 may be made of woven material ornon-woven material. Woven material is generally defined as long fibersthat are intertwined to produce a material. Non-woven material isgenerally defined as randomly joined fibers that are bonded or pressedtogether by adhesive or other means. The randomly joined fibers thatform non-woven material are typically shorter than those used in formingwoven material. The woven material is generally preferred because itprovides an excellent strength to weight ratio that is desirable inwind-resistant applications.

[0023] One type of woven scrim that may be used in polymeric scrim layer12 is a scrim that runs in the machine direction (MD) and the weft ortransverse direction (TD). For example, a scrim having a scrim count of28×4 indicates that the scrim has 28 cords, filaments, or strands perinch in the machine direction and 4 cords, filaments, or strands perinch in the transverse direction. A scrim having cords that run in themachine direction and the weft or transverse direction is commonlyreferred to as a cross-woven scrim. This type of woven scrim may be thetype that is commonly used in applications such as carpet backing.

[0024]FIGS. 2a and 2 b depict embodiments of respective polymeric scrimlayers 112, 212 according to the present invention. As depicted in FIG.2a, the polymeric scrim layer 112 has a first portion 102 and a secondportion 104. The first portion 102 is located in the central area of thepolymeric scrim layer 112 while the second portion 104 is located nearthe periphery of the polymeric scrim layer 112. The second portion 104extends from the periphery of the polymeric scrim layer 112 inwardlytoward the central portion of the polymeric scrim layer 112.

[0025] The first portion 102 has a first machine direction (MD) scrimcount number running in the machine direction 108 and a first transversedirection (TD) scrim count number running in the transverse direction110. Similarly, the second portion 104 has a second MD scrim countnumber running in the machine direction 108 and a second TD scrim countnumber running in the transverse direction 110. At least one of thesecond MD scrim count number and the second TD scrim count number isgreater than the respective first MD scrim count number or the first TDscrim count number. By increasing the scrim count at the periphery ofthe polymeric scrim layer 112, the periphery of the polymeric scrimlayer 112 is reinforced and inhibits the scrim from unraveling.

[0026] As depicted in FIG. 2a, the polymeric scrim layer 112 may alsoinclude a third portion 106. The third portion 106 is located near theperiphery of the polymeric scrim layer 112 opposite the second portion104. The third portion 106 extends from the periphery of the polymericscrim layer 112 inwardly toward the central portion of the polymericscrim layer 112. The third portion 106 has a third MD scrim count numberrunning in the machine direction 108 and a third TD scrim count numberrunning in the transverse direction 110. At least one of the third MDscrim count number and the third TD scrim count number is greater thanthe respective first MD scrim count number or the first TD scrim countnumber. Optionally, the second and third MD scrim count numbers are thesame, and the second and third TD scrim count numbers are the same.

[0027] As depicted in FIGS. 2a and 2 b, the second and third MD scrimcount numbers vary. The MD scrim count number, however, can be variedbased upon the desired use of the sheathing and the cost. FIG. 2adepicts an embodiment where the second MD scrim count number is the sameat the third MD scrim count number and the second and third MD scrimcount numbers are at least two times the first MD scrim count number.The second and third MD scrim count numbers can range from at least twotimes, at least four times, and to at least six times the first MD scrimcount number.

[0028]FIG. 2b depicts another embodiment of the polymeric scrim layer212 according to the present invention. Polymeric scrim layer 212 has afirst portion 202, a second portion 204 and a third portion 206. Thefirst portion 202 is located in the central area of the polymeric scrimlayer 212. The second and third portions 204, 206 are located near theperiphery of the polymeric scrim layer 212 on opposing sides. The firstportion 202 has a first MD scrim count number in the machine direction208 and a first TD scrim count number in the transverse direction 210.The second portion 204 has a second MD scrim count number in the machinedirection 208 and a second TD scrim count number in the transversedirection 210. The third portion 206 has a third MD scrim count numberin the machine direction 208 and a third TD scrim count number in thetransverse direction 210. FIG. 2b depicts an embodiment where the secondand third MD scrim count numbers are the same and the second and thirdMD scrim count numbers are at least six times the first MD scrim countnumber.

[0029] The distance that the second and third portions extend from theperiphery of the polymeric scrim layer 112, 212 varies. The second andthird portions generally extend from the periphery of the polymericscrim layer 112, 212 about ½ of an inch to about 3 inches. The secondand third portions preferably extend from the periphery of the polymericscrim layer 112, 212 about {fraction (1/2)} of an inch to about 1 inch.

[0030] The second portion 104, 204 is preferably located on at least twoopposing portions of the periphery of the polymeric scrim layer 112,212. It is preferred that the second portion extends along two entiresides of the polymeric scrim layer 112, 212. It is also contemplatedthat the third portion 106, 206 may be located on one or more of thesides of the polymeric scrim layer 112, 212 rather than the secondportion 104, 204. The second and third portions are located generallyparallel to the wall supporting structure.

[0031] It is contemplated that various scrim counts may be used informing the polymeric scrim layer having an increased scrim count at theperiphery. Examples of suitable scrim counts that may be used in thecentral portion of the polymeric scrim layer having an increased scrimcount at the periphery include 7×4, 8×6, 9×4, 21×4, 24×4, 28×4, 18×6,and 21×6. It is contemplated that the scrim count number at theperiphery of the polymeric layer will be greater than the scrim countnumber in the central portion and that the selection of the scrim countnumber at the periphery will vary based on the desired use of thesheathing and the cost.

[0032] According to another embodiment, the polymeric scrim layer has auniform scrim count number so as to inhibit failure of the scrim.According to this embodiment, the polymeric scrim layer has an MD scrimcount number which is least 18 and a TD scrim count number which is atleast 4. Examples of suitable scrim counts that may be used where thepolymeric scrim layer has a uniform scrim count number include 21×4,24×4, 28×4, 18×6, and 21×6.

[0033] The polymeric scrim layer 12 may be made of materials such aspolyolefins, polyesters and nylons. Polyolefins that may be used in thepolymeric scrim layer 12 include polypropylenes or polyethylenes. Theterm “polypropylene” as used herein includes polymers of propylene orpolymerizing propylene with other aliphatic polyolefins, such asethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 4-methyl-1-pentene,4-methyl-1-hexene, 5-methyl-1-hexene and mixtures thereof. Polypropylenenot only includes homopolymers of propylene, but also propylenecopolymers comprised of at least 50 mole percent (preferably at least 70mole percent) of a propylene unit and a minor proportion of a monomercopolymerizable with propylene and blends of at least 50 percent byweight of the propylene homopolymer with another polymer.

[0034] The term “polyethylene” as used herein includes low densitypolyethylene (LDPE), medium density polyethylene (MDPE), high densitypolyethylene (HDPE), very low density polyethylene (VLDPE), linear lowdensity polyethylene (LLDPE), metallocene-catalyzed linear low densitypolyethylene (mLLDPE) and combinations thereof.

[0035] LDPE is generally defined as an ethylenic polymer having aspecific gravity of from about 910 to about 925 kg/m³. MDPE is generallydefined as an ethylenic polymer having a specific gravity between theLDPEs and the HDPEs (i.e., from about 925 to about 940 kg/m³). The highdensity polyethylene (HDPE) of the present invention has a specificgravity of from about 940 to about 970 kg/m³. The term polyethylene asused herein includes homopolymers of ethylene and copolymers comprisedof at least 50 mole percent of a ethylene unit (preferably at least 70mole percent) and a minor (i.e., less than 50%) proportion of a monomercopolymerizable with the ethylene unit. The term LDPE as used hereinalso includes physical blends of two or more different homopolymers thatare classified as LDPEs. Similarly, the term MDPE and HDPE may alsoinclude blends of two or more different homopolymers classified as MDPEsand HDPEs, respectively.

[0036] The VLDPE resins have densities ranging from about 880 to about912 kg/m³, more commonly from about 890 to about 910 kg/m³, and meltindices of from about 0.5 to about 5 g/10 min., and from about 1 toabout 3 g/10 min.

[0037] The LLDPE of the present invention generally has from about 1 toabout 20, preferably from about 1 to about 10 weight percent of saidhigher alpha olefin monomer copolymerized therein. In addition, thealpha olefin monomer employed in the ethylenic copolymer may be selectedfrom the group consisting of 1-butene, 3-methyl-1-butene, 3methyl-1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-hexene,1-octene and 1-decene. The LLDPE resins that may be used in the presentinvention have densities ranging from about 890 to about 940 kg/m³, morecommonly from about 900 to about 930 kg/m³, and a melt index (I₂) offrom about 1 to about 10 g/10 min. as determined by ASTM D1238.

[0038] The metallocene-catalyzed polyethylene (mLLDPE) is a polymerhaving a low polydispersity. The low polydispersity polymer may beprepared from a partially crystalline polyethylene resin that is apolymer prepared with ethylene and at least one alpha olefin monomer,e.g., a copolymer or terpolymer. The alpha olefin monomer generally hasfrom about 3 to about 12 carbon atoms, preferably from about 4 to about10 carbon atoms, and more preferably from about 6 to about 8 carbonatoms. The alpha olefin comonomer content is generally below about 30weight percent, preferably below about 20 weight percent, and morepreferably from about 1 to about 15 weight percent. Exemplary comonomersinclude propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-pentene,4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene.

[0039] The low polydispersity polymer has a density of from about 880 toabout 940 kg/m³. The polydispersity polymer generally have a molecularweight distribution, or polydispersity, (M_(w)/M_(n), “MWD”) within therange of from about 1 to about 4, and more typically from about 2 toabout 3. The melt flow ratio (MFR) of these polymers, defined as I₂₀/I₂and as determined in accordance to ASTM D1238, is generally from about12 to about 22 and typically from about 14 to about 20. The melt index(MI), defined as the I₂ value, should be in the range of from about 0.5to about 10 g/10 min. and typically from about 1 to about 5 g/10 min. asdetermined by ASTM D1238.

[0040] An example of a “polyester” includes a polyester resin which is apolycondensation product of a dicarboxylic acid with a dihydroxyalcohol. An example of a “polyethylene terephthalate” includes apolyester resin made from ethylene glycol and terephthalic acid. Anexample of a “nylon” is a polyamide polymer that is characterized by thepresence of the amide group (—CONH).

[0041] It is contemplated that additional polymeric scrim layer(s) canbe added to the sheathing. For example, the sheathing may includepolymeric scrim layers on opposing sides of the polymeric foam layer.

[0042] Polymeric Foam Layer

[0043] The polymeric foam layer 14 is located adjacent to the scrimlayer 12 in FIG. 1. The polymeric foam layer 14 may be made from alkenylaromatic resins, such as polystyrenic resin(s), and polyesters such aspolyethylene terephthalates. The term “alkenyl aromatic polymer” as usedherein includes polymers of aromatic hydrocarbon molecules that containan aryl group joined to an olefinic group with only double bonds in thelinear structure. The polymeric foam layer 14 may also be made frompolyolefinic resins such as LDPEs, HDPEs, LLDPEs, and the like. Thepolymeric foam layer 14 is preferably made from a polystyrenic resin(s),such as a general purpose polystyrene, because of economicalconsiderations at the present time. The polymeric foam layer 14,however, may be made from other polystyrenic resins such as impactpolystyrenes. The impact polystyrenes that are generally used includemedium impact polystyrenes and high impact polystyrenes. The polymericfoam layer 14 may also be made from a combination of virgin and/orreprocessed material. The polymeric foam layer 14, however, may also bemade from polyisocyanurate foam.

[0044] The polymeric foam layer 14 and the polymeric scrim layer 12 maybe bonded by attaching, adhering, fusing or the like. For example, thepolymeric foam layer 14 and the polymeric scrim layer 12 may bethermally bonded to each another depending on the selected materials forforming the layers 12 and 14. Thermal bonding may be accomplished byconventional methods, such as a flameless air torches, heated rolls,radiant heaters and infrared heating.

[0045] Adhesive and Other Layers

[0046] Alternatively, the polymeric foam layer 14 and the polymericscrim layer 12 may be attached with an adhesive layer. This is shown inFIG. 3 where sheathing 30 includes a polymeric scrim layer 12, apolymeric foam layer 14 and an adhesive layer 16. The optional adhesivelayer 16 is located between the polymeric scrim layer 12 and thepolymeric foam layer 14. One type of adhesive that may be used isethylene vinyl acetate (EVA). For example, modified EVAs such as BYNEL®made by DuPONT® or Plexar® made by Equistar Chemicals may be used. Thesemodified EVAs have melt indices generally from about 6.4 to about 25g/10 min. as measured by ASTM D1238 and densities generally from about923 to about 947 kg/m³ as measured by ASTM D11505. BYNEL® is an adhesivethat is designed to bond materials that would not ordinarily adhere toeach other.

[0047] Other adhesives that may be used include block copolymers thatcomprise polymeric regions of styrene-rubber-styrene. For example,KRATON® made by Shell® Chemical Company may be used. Other adhesives arecontemplated in the present invention to bond the polymeric scrim layer12 to the polymeric foam layer 14.

[0048] Additional layers are contemplated in the sheathings of thepresent invention. For example, FIGS. 4, 5 and 6 depict a four-layersheathing, a five-layer sheathing and a seven-layer sheathing,respectively. Referring specifically to FIG. 4, sheathing 40 includes apolymeric scrim layer 12, a polymeric foam layer 14, an adhesive layer16 and an impact polystyrenic layer 18. The polystyrenic layer 18 ispreferably made from a high impact polystyrene because of its desiredstiffness. The polystyrenic layer 18 may be biaxially orientated so asto provide additional durability and flexibility.

[0049]FIG. 5 depicts a sheathing 50 that is similar to the sheathing 40of FIG. 4 except that the sheathing 50 includes an additional impactpolystyrenic layer 18. Sheathing 60 of FIG. 6 comprises the same fivelayers of the sheathing 50 of FIG. 5. The sheathing 60 of FIG. 6,however, also comprises two additional layers. Specifically, thesheathing 60 includes an additional adhesive layer 16 and a polymericfilm layer 20. To provide additional strength and durability, thepolymeric film layer 20 may be made from a polyolefin(s) such aspolypropylene.

[0050] Other layers are contemplated for the sheathings of the presentinvention. For example, the sheathings of the present invention mayinclude radiant barrier layers or flame retardant layers.

[0051] Properties of the Sheathing

[0052] The sheathings of the present invention generally have a flexuralstrength of at least 100 lbs./in.², preferably at least 150 lbs./in.²and most preferably at least 200 lbs./in.² as measured by ASTM D1307.The sheathings of the present invention have excellent strength so as toprovide resistance to high winds. The sheathings of the presentinvention preferably satisfy the structural design requirements as setforth in the H.U.D. Guide for Manufactured Home Standards Programs (9thedition, December 1994) for Wind Zone II conditions (a design wind speedof 100 miles per hour) taken from §3280.305(c) of the Federal Register.The sheathings also preferably satisfy the structural designrequirements as set forth in H.U.D. Guide for Manufactured HomeStandards Programs (9th edition, December 1994) for Wind Zone IIIconditions (a design wind speed of 110 mph) taken from §3280.305(c) ofthe Federal Register.

[0053] The sheathings of the present invention may be formed into anumber of shapes. For example, the sheathing may be a flat sheet or afolded or hinged board (typically referred to as a fanfolded sheathing).The fanfold sheathing is designed to unfold at its hinges and includes anumber of individual panels.

[0054] The sheathings of the present invention may be manufactured in avariety of sizes. Popular sizes used in the housing market include a 4foot by 7 foot (4′×7′), 4′×7½′, 4′×8′ and 4′×9′ flat sheets. Otherpopular sizes in the housing market include a 4′×50′ fanfolded sheathingwhich includes a number of individual panels. If a fanfolded sheathingis used, it is preferred to have cross-members in the wall supportingstructure for which the fanfolded sheathing may be attached.

[0055] The thickness of the sheathings may also vary. The thickness ofthe sheathing is generally from about {fraction (1/4)} of an inch toabout 3 inches as measured by ASTM C303. The thickness of the sheathingis preferably from about {fraction (1/4)} of an inch to about {fraction(3/4)} of an inch as measured by ASTM C303.

[0056] The layers of the sheathings typically vary in their respectiveweight percent relative to each other. The sheathings generally comprisefrom about 2 wt. % to about 30 wt. % of the polymeric scrim layer(s) 12.The sheathings generally comprise from about 25 wt. % to about 99 wt. %of the polymeric foam layer(s) 14. The sheathings generally comprisefrom 0 wt. % to about 15 wt. % of the adhesive layer(s) 16. It iscontemplated that the remainder of the sheathings may include otheroptional layers. The sheathings generally comprise from 0 wt. % to about50 wt. % of the impact polystyrenic layer(s) 18 and from 0 wt. % toabout 50 wt. % of the polymeric film layer(s) 20. The sheathingspreferably comprise from about 2 to about 25 wt. %, and most preferablyfrom about 4 wt. % to about 20 wt. % of the polymeric scrim layer(s) 12.The sheathings preferably comprise from about 30 to about 95 wt. %, andmost preferably from about 40 wt. % to about 90 wt. % of the polymericfoam layer(s) 14. Preferably, the sheathings comprise from about 1 toabout 10 wt. %, and most preferably from about 1 wt. % to about 7 wt. %of the adhesive layer(s) 16. The sheathings preferably comprise fromabout 5 to about 35 wt. %, and most preferably from about 5 wt. % toabout 30 wt. % of the impact polystyrenic layer(s) 18. The sheathingspreferably comprise from 0 to about 25 wt. %; and most preferably from 0wt. % to about 20 wt. % of the polymeric film layer(s) 20.

[0057] The sheathings of the present invention may be used in variousbuildings such as prefabricated housing (also referred to asmanufactured housing), site built housing, and remodeling. The sheathingmay be installed to a wall supporting structure. An example is shown inFIG. 7 where a sheathing 52 is installed to a plurality of wallsupporting structures 22 using the polymeric scrim layer 112 of FIG. 2a.The sheathing 52 a has been cut-away to depict the various layers 112,14, 16 and 18, while sheathing 52 b has not been cut-away in FIG. 7.FIG. 7 also shows siding 56 being located on an exterior surface of thesheathing 52.

[0058] The sheathing 52 of FIG. 7 may be installed to the plurality ofwall supporting structure 22 by the use of fasteners (not shown). Thefastener may be a mechanical fastener such as a staple or nail.According to the embodiment depicted in FIG. 7, the polymeric scrimlayer 112 of the sheathing 52 includes a first portion 102, a secondportion 104, and a third portion 106 opposite the second portion 104.The second and third portions 104, 106 are located generally parallel tothe wall supporting structure 22.

[0059] It is contemplated that the sheathing of the present inventionmay be used in a roofing application to provide additional strength, toresist wind uplift and to provide durability that minimizes breakageduring handling and installation. The sheathing may be used as anunderlayment for low slope roofs.

PROCESS OF THE PRESENT INVENTION

[0060] According to one process of the present invention, a polymericweb of foam is provided to form the polymeric foam layer. The processmay use a single twin screw extruder or a tandem foam extrusion line.For example, the process begins by loading pellets of a polymericresin(s) such as polystyrenic foam resin. The polymeric resins in theirsolid form are added into an extrusion hopper.

[0061] A nucleating agent (also referred to as cell size control agent)or combination of such nucleating agents may be employed in the processof the present invention for advantages such as their capability forregulating cell formation and morphology. The amount of nucleating agentto be added depends upon the desired cell size, the selected blowingagent and the density of the polymeric composition. Known nucleatingagents such as talc, mixtures of sodium bicarbonate and citric acid, andthe like may be employed in the present invention.

[0062] It is contemplated that stability control agent(s) may also beadded to the polymeric resin(s), including conventional stabilitycontrol agents. Some examples of stability control agents that may beused include, but are not limited to, glycerol monostearate, saturatedhigher fatty acid amides and glycerol monoester of a C₂₀-C₂₄ fatty acid.

[0063] If desired, fillers, colorants, light and heat stabilizers,plasticizers, chemical blowing agents, flame retardants, foamingadditives and plastic compounding agents may be added to the polymericcomposition. The polymeric composition comprises the polymeric resinand, if added, the nucleating agent, the stability control agent andadditives. The polymeric composition is conveyed through a feed zone ofthe extruder and heated at a temperature sufficient to form a polymericmelt.

[0064] A physical blowing agent may be added at the injection port areaof the extruder in an appropriate ratio to the target density. Theselected blowing agent may be any type that is capable of producing foamwith the selected resin. Some examples of blowing agents includephysical blowing agents such as halocarbons, hydrocarbons orcombinations thereof. Examples of these include commercially availablehydrofluorocarbons, such as HFC-152a and HFC-134a,hydrochlorofluorocarbons, such as HCFC-22 or HCFC-142b, and the C₃-C₆hydrocarbons. Other types of blowing agents include carbon dioxide. Thepolymeric composition and the selected blowing agent are thoroughlymixed within the extruder in a mixing zone and subsequently cooled in acooling zone. The cooled polymeric-blowing agent melt is extrudedthorough a die.

[0065] One method of the present invention for making a three-layersheathing is shown in a schematic flow diagram in FIG. 8. In the processof FIG. 8, the polymeric foam is extruded from an extruder 70 through around die 72. After exiting the round die 72, the extrudate expands whenentering a lower pressure region (e.g., the atmosphere) and forms apolymeric web of foam. The polymeric web of foam is stretched over asizing mandrel 74 to size and then is slit to form the web of foam. Thepolymeric web of foam will eventually be used in forming the polymericfoam layer 14.

[0066] At least one of the outer surfaces of the polymeric web of foamis typically cooled so as to form a “skin.” The skin is typically abouta few thousands (or a few mils) thick, but may vary depending on thecooling employed. The skin provides additional strength and alsoprovides a smoother surface that is more aesthetically pleasing to aconsumer if the polymeric layer is visible to the customer. It iscontemplated that cooling methods may be accomplished by using air andwater. The skinning may be performed, for example, by stretching thepolymeric foam of web 76 over the sizing mandrel 74 with optionalcooling wherein either surface of the polymeric foam of web 76 iscooled. It is contemplated that one or more of the surfaces of thepolymeric web of foam may be cooled.

[0067] The polymeric foam web 76 proceeds to travel around a S-wrap ofrollers 78 a-c in which roller 78 a is an idler roller and rollers 78 band 78 c are driven or pull rollers. The driven rollers 78 b, 78 cassist in moving the polymeric foam web 76 through the process of thepresent invention. The polymeric foam web 76 proceeds between two drivenrollers 80 a,b. Driven rollers 80 a,b assist in maintaining a consistentsurface on which a web of adhesive 82 a is added via an adhesive coatingor a laminating machine 82. The adhesive machine 82 may be anyconventional machine that is capable of applying the adhesive web 82 ato the polymeric foam web 76. The adhesive machine 82 may coextrude theweb of adhesive 82 a with a second web, such as a web of impactpolystyrene (not shown).

[0068] At the about the same time, a web of scrim 84 a is added via aroll unwind cart system 84. The cart system 84 may include an edgealignment system to properly align the web of scrim 84 a to thepolymeric foam web 76. After exiting the driven rollers 80 a,b, thepolymeric foam web 76, the web of adhesive 82 a, and the web of scrim 84a form a sheathing web 86.

[0069] It is contemplated that the sheathing web 86 may be processed toinclude printing on one or more surfaces or other treatments. Theprocess of FIG. 8 includes an optional printer 88 that prints on onesurface of the sheathing web 86. It is contemplated that the printingmay occur on the polymeric foam web 76 before the webs of adhesive andscrim are added to the polymeric foam web 76. The sheathing web 86proceeds around a series of rollers 90 a-90 d and then to an optionaledge trim system 92. The edge trim system assists in sizing thesheathing web 86 to be used in forming the sheathing of the presentinvention.

[0070] As shown in FIG. 8, the sheathing web 86 proceeds through anoptional perforating creasing machine 94. The perforating creasingequipment 94 may include any conventional equipment that is capable offolding the sheathing web 86 of the present invention into a fanfoldsheathing web. Of course, if flat sheathing is desired, the creasingequipment 94 should not be included in the process. A perforatingmachine, however, may be used in producing a flat sheathing. Thesheathing web is then cut to a desired dimension by shearing equipment96. The shearing equipment 96 may be any equipment capable of cuttingthe sheathing web 86 into desired dimensions. It is also contemplatedthat other finishing operations may occur such as stacking, counting,packaging and trimming. It is also contemplated that variousmeasurements may be taken throughout the process to ensure consistentmeasurements.

[0071] According to a second process of the present invention (notshown), additional layers may be added in forming other sheathings, suchas those described above. For example, a machine (not shown) may beadded to the process of FIG. 8 that is adapted to add an additionalimpact polystyrenic web to the polymeric web of foam.

EXAMPLES Example 1

[0072] Negative wind pressure load tests were conducted on samples ofsheathing (“Sheathing 1”) using a 2×4 (1{fraction (1/2)} inches×3{fraction (1/2)} inches) stud wall supporting structure. Sheathing 1had dimensions of 48 inches by 90 inches (48″×90″). Sheathing 1consisted of five layers with the first layer being a wovenpolypropylene scrim having a scrim count of 28×4. The second layer wasmade of a BYNEL® adhesive. The third and fifth layers were made of highimpact polystyrene. The second layer was located between the first andthird layers. The fourth layer was a polystyrene foam and was locatedbetween the third and fifth layers. This is a similar structure as shownabove in FIG. 7. The following describes the test specimens that wereused in Example 1.

Example 1

[0073] Specimen Description

[0074] A. Materials

[0075] 1. Stud: Double 2×4, Stud Grade spruce pine fur (SPF) spaced at16″ on center (o.c.)

[0076] 2. Top Plate: Single 1×4, Ungraded SPF

[0077] 3. Bottom Plate: Single 1×4, Ungraded SPF

[0078] 4. Gypsum: {fraction (5/16)}″×48″×90″ Georgia Pacific

[0079] 5. Siding: Georgia Pacific 4.5 Lap Vinyl Siding with a nailingflange thickness of 0.036 inch

[0080] 6. Adhesive: PVA

[0081] B. Fastening

[0082] Top plate attached to studs with three (3)-{fraction(7/16)}″×1¾″×15 gauge (Ga.) Staples.

[0083] Bottom plate attached to studs with three (3)-{fraction(7/16)}″×1¾″×15 Ga. Staples.

[0084] Sheathing 1 fastened with 1″×1{fraction (1/2)}″×16 Ga. staples at3″ o.c. on single framing members.

[0085] Gypsum fastened to studs with {fraction (3/16)}″×1″×19 Ga.staples at 16″ o.c. per strip of siding.

[0086] Gypsum glued to frame with a {fraction (3/8)}″ bead of PVA glueon all framing members.

[0087] Siding fastened to Sheathing 1 into the studs with {fraction(7/16)}″×1½″×16 Ga. staples at 16″ o.c. per strip of siding.

[0088] C. Construction

[0089] The 48″×90″ test sample was first assembled with 2×4 studs thatwere 87.75 inches long. The top and bottom plates were 49.5 inches long.Polyethylene sheeting (6 mil) was placed between the 2×4 framing andSheathing 1. The framing was then squared with Sheathing 1 and fastenedas described above. The horizontal vinyl siding was fastened throughSheathing 1 and into the studs. The {fraction (5/16)}″ gypsum was thenfastened to the opposite side of the frame as described above. Glue wasallowed to cure for 7 days before the testing began. Materials for theassemblies tested were commercially purchased products.

Example 1

[0090] Test Setup and Procedure

[0091] The testing was conducted in accordance with the ultimate loadtest procedures in H.U.D. Guide for Manufactured Home Standards Programs(9th edition, December 1994) taken from §3280.401(b) of the FederalRegister. An 11-{fraction (1/4)}″ deep wood box was built 1″ wider and1″ longer than the test sample. The top and bottom plates of the testsamples were secured to 2×4 ledgers. The test samples were placedvertically on the test fixture with the vinyl siding facing down and theledgers bearing on top of the wood box. The polyethylene sheeting (6mil) that was placed between the wall framing and Sheathing 1 was sealedto the table. This allowed the entire surface of Sheathing 1 to beexposed to the full negative loads.

[0092] The uniform load was applied by evacuating the air below the testspecimen using a vacuum pump. The applied load was measured with a watermanometer capable of reading in 0.1 inch increments. The load wasapplied in approximate ¼ design live load increments at 10 minuteintervals until 1.25 times design load was reached. The load was thenincreased to 2.5 times design load or until failure occurred. The loadin inches of water column was converted to pounds per square foot (psf)by using the conversion of 1 inch (of water column) to 5.2 psf.

[0093] Deflection readings were taken using dial indicators capable ofreading in 0.001″ increments. The deflections were taken at thequarter-points of the center stud.

Example 1

[0094] Results

[0095] Three specimens (S1, S2, and S3) using {fraction (5/16)}″ GeorgiaPacific Gypsum were tested for corner Wind Zone III requirements. Theproduct sold by Georgia Pacific Corporation that was used was {fraction(5/16)}″ PreDeck® Gypsum Board. The ultimate load in pounds per squarefoot (psf) was determined in accordance with H.U.D. Guide forManufactured Home Standards Programs (9th edition, December 1994) takenfrom §3280.401(b) of the Federal Register. The average of these threespecimens is shown under the “AVG.” column. The results are as followsin Table 1. TABLE 1 ULTIMATE EXPER. LOAD (PSF) AVG. DEFLECTION NO. S1 S2S3 (PSF) (PASS/FAIL) WINDZONE 1 156 150.8 161.2 156 PASSED III Corner

[0096] The samples in Experiment 1 satisfied the ultimate load under acorner condition for Wind Zone III. In addition, the samples inExperiment 1 also passed the deflection test under a corner conditionfor Wind Zone III. The ultimate load requirement for Wind Zone III for anon-corner condition is 115 psf, while the ultimate load requirement forWind Zone III for a corner condition is 145 psf.

Example 2

[0097] Negative wind pressure load tests were conducted on samples of48″×90″ Sheathing 1 (described above in Example 1). The followingdescribes the test specimens that were used in Example 2.

Example 2

[0098] Specimen Description

[0099] A. Materials

[0100] 1. Stud: 2×4, Stud Grade SPF spaced at 16″ o.c.

[0101] 2. Top Plate: Single 1×4, Ungraded SPF

[0102] 3. Bottom Plate: Single 1×4, Ungraded SPF

[0103] 4. Gypsum: {fraction (5/16)}″×48″×90″ Gypsum, Georgia-Pacific

[0104] 5. Siding: Georgia Pacific 4.5 Lap Vinyl Siding with a nailingflange thickness of 0.036 inch

[0105] 6. Adhesive: PVA

[0106] B. Fastening

[0107] Top plate attached to studs with three (3)-{fraction(7/16)}″×1¾″×15 Ga. Staples.

[0108] Bottom plate attached to studs with three (3)-{fraction(7/16)}″×1¾″×15 Ga. Staples.

[0109] Sheathing 1 fastened with 1″×1½″×16 Ga. staples at 3″ o.c. onframing members.

[0110] Gypsum fastened to studs with {fraction (3/16)}″×1″×19 Ga.Staples at 16″ o.c. per strip of siding.

[0111] Gypsum glued to frame with a ⅜″ bead of PVA glue on all framingmembers.

[0112] Siding fastened to sheathing into the studs with {fraction(7/16)}″×1 ½″×16 Ga. staples at 16″ o.c. per strip of siding.

[0113] C. Construction

[0114] The construction was similar to that described above in Example1.

Example 2

[0115] Test Setup and Procedure

[0116] The test setup and procedure were similar to that described abovein Example 1.

Example 2

[0117] Results

[0118] Three specimens (S1, S2, S3) using {fraction (5/16)}″Georgia-Pacific Gypsum were tested for non-corner Wind Zone IIIrequirements. The results are as follows in Table 2. TABLE 1 ULTIMATEEXPER. LOAD (PSF) AVG. DEFLECTION NO. S1 S2 S3 (PSF) (PASS/FAIL)WINDZONE 2 135.2 140.4 135.2 136.9 PASSED III Corner

[0119] The samples in Experiment 2 passed the requirement for ultimateload under a non-corner condition for Wind Zone III. In addition, thesamples in Experiment 2 also passed the deflection test under anon-corner condition for Wind Zone III.

[0120] While the present invention has been described with reference toone or more particular embodiments, those skilled in the art willrecognize that many changes may be made thereto without departing fromthe spirit and scope of the present invention. Each of these embodimentsand obvious variations thereof is contemplated as falling within thespirit and scope of the claimed invention, which is set forth in thefollowing claims.

What is claimed is:
 1. A sheathing adapted to be fastened to at leastone wall supporting structure, comprising at least two layers: (a) afirst layer comprising a polymeric foam layer; and (b) a second layercomprising a polymeric scrim, the polymeric scrim including a firstportion and a second portion, the second portion being located near theperiphery of the polymeric scrim layer, the first portion having a firstmachine direction (MD) scrim count number and a first transversedirection (TD) scrim count number, the second portion having a second MDscrim count number and a second TD scrim count number, at least one ofthe second MD scrim count number and the second TD scrim count numberbeing greater than the respective first MD scrim count number or thefirst TD scrim count number.
 2. The sheathing of claim 1, wherein thesecond layer includes a third portion, the third portion being locatednear the periphery of the polymeric scrim layer opposite the secondportion, the third portion having a third MD scrim count number and athird TD scrim count number, at least one of the third MD scrim countnumber and the third TD scrim count number being greater than therespective first MD scrim count number or the first TD scrim countnumber.
 3. The sheathing of claim 2, wherein the second and third MDscrim count numbers are the same.
 4. The sheathing of claim 2, whereinthe second and third TD scrim count numbers are the same.
 5. Thesheathing of claim 2, wherein the second and third MD scrim countnumbers are the same and the second and third TD scrim count numbers arethe same.
 6. The sheathing of claim 1, wherein the second MD scrim countnumber is at least about two times the first MD scrim count number. 7.The sheathing of claim 2, wherein the second and third MD scrim countnumbers are at least about two times the first MD scrim count number. 8.The sheathing of claim 1, wherein the second MD scrim count number is atleast about four times the first MD scrim count number.
 9. The sheathingof claim 2, wherein the second and third MD scrim count numbers are atleast about four times the first MD scrim count number.
 10. Thesheathing of claim 1, wherein the second MD scrim count number is atleast about six times the first MD scrim count number.
 11. The sheathingof claim 2, wherein the second and third MD scrim count numbers are atleast about six times the first MD scrim count number.
 12. The sheathingof claim 1 further including a third layer comprising an adhesive, thethird layer being located between the first and the second layers. 13.The sheathing of claim 12 further including a fourth layer being locatedadjacent to the second layer, the fourth layer comprising an impactpolystyrene.
 14. The, sheathing of claim 13, wherein the impactpolystyrene is a high impact polystyrene.
 15. The sheathing of claim 13further including a fifth layer being located adjacent to the thirdlayer, the fifth layer comprising an impact polystyrene.
 16. Thesheathing of claim 1, wherein the first layer is a polyolefin foam. 17.The sheathing of claim 1, wherein the first layer is a polyethyleneterephthalate foam.
 18. The sheathing of claim 1, wherein the firstlayer is a polystyrenic foam.
 19. The sheathing of claim 1, wherein thepolymeric scrim is made from polyolefins, polyesters or nylon.
 20. Thesheathing of claim 1, wherein the polymeric scrim is made frompolyolefins, the polyolefinic scrim being made of polypropylene,polyethylene or the combination thereof.
 21. The sheathing of claim 1,wherein the polymeric scrim is made from polypropylene.
 22. Thesheathing of claim 1, wherein the polymeric scrim is polypropylene andthe first layer is a polystyrenic foam.
 23. The sheathing of claim 1,wherein the polymeric scrim is woven.
 24. The sheathing of claim 23,wherein the polymeric scrim is cross-woven.
 25. The sheathing of claim1, wherein the polymeric scrim is non-woven.
 26. The sheathing of claim1, wherein the thickness of the sheathing is from about 0.25 inch toabout 3 inches.
 27. The sheathing of claim 2, wherein the second andthird portions extend from the periphery of the polymeric scrim layerinwardly about 2 to about 3 inches.
 28. The sheathing of claim 1,wherein the second and third portions are located generally parallel tothe at least one wall supporting structure.
 29. A method of using asheathing in a building, the method comprising: (a) providing asheathing comprising at least two layers, the first layer comprises apolymeric foam layer, a second layer comprising a polymeric scrim, thepolymeric scrim including a first portion and a second portion, thesecond portion being located near the periphery of the polymeric scrimlayer, the first portion having a first machine direction (MD) scrimcount number and a first transverse direction (TD) scrim count number,the second portion having a second MD scrim count number and a second TDscrim count number, at least one of the second MD scrim count number andthe second TD scrim count number being greater than the respective firstMD scrim count number or the first TD scrim count number; (b) providingat least one wall supporting structure; and (c) installing the sheathingto at least one of the wall supporting structures.
 30. The method ofclaim 29, wherein the second layer includes a third portion, the thirdportion being located near the periphery of polymeric scrim layeropposite the second portion, the third portion having a third MD scrimcount number and a third TD scrim count number, at least one of thethird MD scrim count number and the third TD scrim count number beinggreater than the respective first MD scrim count number or the first TDscrim count number.
 31. The method of claim 30, wherein the step ofinstalling the sheathing to at least one of the wall supportingstructures includes positioning the second and third portions in alocation that is generally parallel to the at least one wall supportingstructure.
 32. The method of claim 29, wherein the second scrim count islocated on at least two opposing portions of the periphery of thepolymeric scrim layer.
 33. The method of claim 30, wherein the secondand third MD scrim count numbers are the same.
 34. The method of claim29, wherein the step of installing includes the use of a fastener. 35.The method of claim 34, wherein the fastener is a staple or a nail. 36.The method of claim 29, wherein the building is prefabricated housing ora site built housing.
 37. The method of claim 34, wherein the fastenerremains connected to the wall supporting structure.
 38. A sheathingadapted to be fastened to at least one wall supporting structure,comprising at least three layers: (a) a first layer comprising apolymeric foam layer; (b) a second layer comprising a polymericcross-woven scrim, the polymeric scrim including a first portion and asecond portion, the second portion being located near the periphery ofthe polymeric scrim layer, the first portion having a first machinedirection (MD) scrim count number and a first transverse direction (TD)scrim count number, the second portion having a second MD scrim countnumber and a second TD scrim count number, at least one of the second MDscrim count number and the second TD scrim count number being greaterthan the respective first MD scrim count number or the first TD scrimcount number; and (d) a third layer comprising an impact polystyrene,the third layer being located between the first and the second layers.39. The sheathing of claim 38, wherein the second layer includes a thirdportion, the third portion being located near the periphery of thepolymeric scrim layer opposite the second portion, the third portionhaving a third MD scrim count number and a third TD scrim count number,at least one of the third MD scrim count number and the third TD scrimcount number being greater than the respective first MD scrim countnumber or the first TD scrim count number.
 40. The sheathing of claim 38further including a fourth layer comprising an impact polystyrene, thefourth layer being located adjacent to the first layer on an opposingside from the third layer.
 41. The sheathing of claim 40 furtherincluding a fifth layer comprising an adhesive, the fifth layer beinglocated between the second and third layers.
 42. The sheathing of claim38 further including a fourth layer made of an adhesive, the fourthlayer being located between the second and third layers.
 43. Thesheathing of claim 38, wherein the polymeric foam is a polyolefin foam.44. The sheathing of claim 38, wherein the polymeric foam is apolystyrenic foam.
 45. The sheathing of claim 38, wherein the polymericfoam is polyethylene terephthalate foam.
 46. The sheathing of claim 38,wherein the cross-woven scrim is a cross-woven polypropylene scrim. 47.The sheathing of claim 38, wherein the polymeric foam is polystyrenicfoam, the polymeric scrim is a woven polypropylene scrim and wherein thesheathing further includes a fourth layer and a fifth layer, the fourthlayer comprising an impact polystyrene and is located adjacent to thesecond layer on an opposing side from the third layer and the fifthlayer comprises an adhesive and is located between the second and thirdlayers.
 48. The sheathing of claim 40 further including a sixth layercomprising a polypropylene layer and a seventh layer comprising anadhesive, the sixth layer being located adjacent to the first layer onan opposing side from the third layer, the seventh layer being locatedadjacent to the sixth layer on an opposing side from the first layer.49. The sheathing of claim 39, wherein the second and third MD scrimcount numbers are the same.
 50. The sheathing of claim 39, wherein thesecond and third TD scrim count numbers are the same.
 51. The sheathingof claim 39, wherein the second and third MD scrim count numbers are thesame and the second and third TD scrim count numbers are the same. 52.The sheathing of claim 38, wherein the second MD scrim count number isat least about two times the first MD scrim count number.
 53. Thesheathing of claim 39, wherein the second and third MD scrim countnumbers are at least about two times the first MD scrim count number.54. The sheathing of claim 38, wherein the second MD scrim count numberis at least about four times the first MD scrim count number.
 55. Thesheathing of claim 39, wherein the second and third MD scrim countnumbers are at least about four times the first MD scrim count number.56. The sheathing of claim 38, wherein the second MD scrim count numberis at least about six times the first MD scrim count number.
 57. Thesheathing of claim 39, wherein the second and third MD scrim countnumbers are at least about six times the first MD scrim count number.58. The sheathing of claim 38, wherein the thickness of the sheathing isfrom about 0.25 inch to about 3 inches.
 59. The sheathing of claim 39,wherein the second and third portions extend from the periphery of thepolymeric scrim layer inwardly about 2 to about 3 inches.
 60. Thesheathing of claim 38, wherein the second and third portions are locatedgenerally parallel to the at least one wall supporting structure.
 61. Asheathing adapted to be fastened to at least one wall supportingstructure comprising at least two layers: (a) a first layer comprising apolymeric foam layer; and (c) a second layer comprising a polymericscrim having a uniform scrim count number, wherein the polymeric scrimhas a machine direction (MD) scrim count number and a transversedirection (TD) scrim count number, wherein the MD scrim count number isat least 18 and the TD scrim count number is at least
 4. 62. Thesheathing of claim 61, wherein the MD scrim count number is at least 21.63. The sheathing of claim 61, wherein the TD scrim count number is atleast 6.